Anemia is a blood disorder that occurs when the total volume of red blood cells and/or the amount of hemoglobin in the red blood cells is reduced below normal values. Anemia causes symptoms such as general fatigue, weakness, interrupted concentration, and shortness of breath. Heart failure (HF) is a common comorbidity with anemia. Very severe anemia prompts the body to attempt to increase cardiac output which may lead to heart failure. On the other hand, severe heart failure leads to heart failure decompensation which produces a fluid overload in the blood, causing an increase in plasma without a corresponding increase in red blood cells, which in turn results in anemia.
Anemia is often treated by pharmaceuticals, for example, by administering an iron supplement, vitamin B12, folic acid, recombinant erythropoietin, and/or erythropoiesis-stimulating agents such as epoetin and/or darbepoetin. Erythropoiesis-stimulating agents ultimately stimulate an increase the production of red blood cells. Although administration of erythropoiesis-stimulating agents and/or other pharmaceuticals is beneficial to treat anemia and may concurrently improve heart failure symptoms, such treatments can increase the risk of thromboembolism. Other treatments for severe anemia include blood transfusions which also pose risks to the patient.
Anemia is most commonly detected by performing patient-external blood tests that include measuring hemoglobin (the iron-carrying part of red blood cells), or by determining hematocrit (the volume of red blood cells in a specified amount of blood). Anemia assessments are usually carried out in clinical settings, therefore days or weeks may elapse between tests. The lapse of time between tests hinders the timely delivery of therapy.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading the present specification, there is a need in the art for methods and systems that provide improved approaches for detecting and treating anemia, particularly for patients with heart failure. The present invention fulfills these and other needs and provides for other improvements over the prior art.